syncprov.c

/* $OpenLDAP$ */
/* syncprov.c - syncrepl provider */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 2004-2005 The OpenLDAP Foundation.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */
/* ACKNOWLEDGEMENTS:
 * This work was initially developed by Howard Chu for inclusion in
 * OpenLDAP Software.
 */

#include "portable.h"

#ifdef SLAPD_OVER_SYNCPROV

#include <ac/string.h>
#include "lutil.h"
#include "slap.h"
#include "config.h"
#include "ldap_rq.h"

/* A modify request on a particular entry */
typedef struct modinst {
	struct modinst *mi_next;
	Operation *mi_op;
} modinst;

typedef struct modtarget {
	struct modinst *mt_mods;
	struct modinst *mt_tail;
	Operation *mt_op;
	ldap_pvt_thread_mutex_t mt_mutex;
} modtarget;

/* A queued result of a persistent search */
typedef struct syncres {
	struct syncres *s_next;
	struct berval s_dn;
	struct berval s_ndn;
	struct berval s_uuid;
	struct berval s_csn;
	char s_mode;
	char s_isreference;
} syncres;

/* Record of a persistent search */
typedef struct syncops {
	struct syncops *s_next;
	struct berval	s_base;		/* ndn of search base */
	ID		s_eid;		/* entryID of search base */
	Operation	*s_op;		/* search op */
	int		s_rid;
	struct berval s_filterstr;
	int		s_flags;	/* search status */
#define	PS_IS_REFRESHING	0x01
#define	PS_IS_DETACHED		0x02
#define	PS_WROTE_BASE		0x04
#define	PS_FIND_BASE		0x08

	int		s_inuse;	/* reference count */
	struct syncres *s_res;
	struct syncres *s_restail;
	struct re_s	*s_qtask;	/* task for playing psearch responses */
#define	RUNQ_INTERVAL	36000	/* a long time */
	ldap_pvt_thread_mutex_t	s_mutex;
} syncops;

/* A received sync control */
typedef struct sync_control {
	struct sync_cookie sr_state;
	int sr_rhint;
} sync_control;

#if 0 /* moved back to slap.h */
#define	o_sync	o_ctrlflag[slap_cids.sc_LDAPsync]
#endif
/* o_sync_mode uses data bits of o_sync */
#define	o_sync_mode	o_ctrlflag[slap_cids.sc_LDAPsync]

#define SLAP_SYNC_NONE					(LDAP_SYNC_NONE<<SLAP_CONTROL_SHIFT)
#define SLAP_SYNC_REFRESH				(LDAP_SYNC_REFRESH_ONLY<<SLAP_CONTROL_SHIFT)
#define SLAP_SYNC_PERSIST				(LDAP_SYNC_RESERVED<<SLAP_CONTROL_SHIFT)
#define SLAP_SYNC_REFRESH_AND_PERSIST	(LDAP_SYNC_REFRESH_AND_PERSIST<<SLAP_CONTROL_SHIFT)

/* Record of which searches matched at premodify step */
typedef struct syncmatches {
	struct syncmatches *sm_next;
	syncops *sm_op;
} syncmatches;

/* Session log data */
typedef struct slog_entry {
	struct slog_entry *se_next;
	struct berval se_uuid;
	struct berval se_csn;
	ber_tag_t	se_tag;
} slog_entry;

typedef struct sessionlog {
	struct berval	sl_mincsn;
	int		sl_num;
	int		sl_size;
	slog_entry *sl_head;
	slog_entry *sl_tail;
	ldap_pvt_thread_mutex_t sl_mutex;
} sessionlog;

/* The main state for this overlay */
typedef struct syncprov_info_t {
	syncops		*si_ops;
	struct berval	si_ctxcsn;	/* ldapsync context */
	int		si_chkops;	/* checkpointing info */
	int		si_chktime;
	int		si_numops;	/* number of ops since last checkpoint */
	int		si_nopres;	/* Skip present phase */
	int		si_usehint;	/* use reload hint */
	time_t	si_chklast;	/* time of last checkpoint */
	Avlnode	*si_mods;	/* entries being modified */
	sessionlog	*si_logs;
	ldap_pvt_thread_mutex_t	si_csn_mutex;
	ldap_pvt_thread_mutex_t	si_ops_mutex;
	ldap_pvt_thread_mutex_t	si_mods_mutex;
	char		si_ctxcsnbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
} syncprov_info_t;

typedef struct opcookie {
	slap_overinst *son;
	syncmatches *smatches;
	struct berval sdn;	/* DN of entry, for deletes */
	struct berval sndn;
	struct berval suuid;	/* UUID of entry */
	struct berval sctxcsn;
	int sreference;	/* Is the entry a reference? */
} opcookie;

typedef struct fbase_cookie {
	struct berval *fdn;	/* DN of a modified entry, for scope testing */
	syncops *fss;	/* persistent search we're testing against */
	int fbase;	/* if TRUE we found the search base and it's still valid */
	int fscope;	/* if TRUE then fdn is within the psearch scope */
} fbase_cookie;

static AttributeName csn_anlist[3];
static AttributeName uuid_anlist[2];

/* Build a LDAPsync intermediate state control */
static int
syncprov_state_ctrl(
	Operation	*op,
	SlapReply	*rs,
	Entry		*e,
	int		entry_sync_state,
	LDAPControl	**ctrls,
	int		num_ctrls,
	int		send_cookie,
	struct berval	*cookie )
{
	Attribute* a;
	int ret;

	BerElementBuffer berbuf;
	BerElement *ber = (BerElement *)&berbuf;

	struct berval	entryuuid_bv = BER_BVNULL;

	ber_init2( ber, 0, LBER_USE_DER );
	ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );

	ctrls[num_ctrls] = op->o_tmpalloc( sizeof ( LDAPControl ), op->o_tmpmemctx );

	for ( a = e->e_attrs; a != NULL; a = a->a_next ) {
		AttributeDescription *desc = a->a_desc;
		if ( desc == slap_schema.si_ad_entryUUID ) {
			entryuuid_bv = a->a_nvals[0];
			break;
		}
	}

	/* FIXME: what if entryuuid is NULL or empty ? */

	if ( send_cookie && cookie ) {
		ber_printf( ber, "{eOON}",
			entry_sync_state, &entryuuid_bv, cookie );
	} else {
		ber_printf( ber, "{eON}",
			entry_sync_state, &entryuuid_bv );
	}

	ctrls[num_ctrls]->ldctl_oid = LDAP_CONTROL_SYNC_STATE;
	ctrls[num_ctrls]->ldctl_iscritical = (op->o_sync == SLAP_CONTROL_CRITICAL);
	ret = ber_flatten2( ber, &ctrls[num_ctrls]->ldctl_value, 1 );

	ber_free_buf( ber );

	if ( ret < 0 ) {
		Debug( LDAP_DEBUG_TRACE,
			"slap_build_sync_ctrl: ber_flatten2 failed\n",
			0, 0, 0 );
		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
		return ret;
	}

	return LDAP_SUCCESS;
}

/* Build a LDAPsync final state control */
static int
syncprov_done_ctrl(
	Operation	*op,
	SlapReply	*rs,
	LDAPControl	**ctrls,
	int			num_ctrls,
	int			send_cookie,
	struct berval *cookie,
	int			refreshDeletes )
{
	int ret;
	BerElementBuffer berbuf;
	BerElement *ber = (BerElement *)&berbuf;

	ber_init2( ber, NULL, LBER_USE_DER );
	ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );

	ctrls[num_ctrls] = op->o_tmpalloc( sizeof ( LDAPControl ), op->o_tmpmemctx );

	ber_printf( ber, "{" );
	if ( send_cookie && cookie ) {
		ber_printf( ber, "O", cookie );
	}
	if ( refreshDeletes == LDAP_SYNC_REFRESH_DELETES ) {
		ber_printf( ber, "b", refreshDeletes );
	}
	ber_printf( ber, "N}" );

	ctrls[num_ctrls]->ldctl_oid = LDAP_CONTROL_SYNC_DONE;
	ctrls[num_ctrls]->ldctl_iscritical = (op->o_sync == SLAP_CONTROL_CRITICAL);
	ret = ber_flatten2( ber, &ctrls[num_ctrls]->ldctl_value, 1 );

	ber_free_buf( ber );

	if ( ret < 0 ) {
		Debug( LDAP_DEBUG_TRACE,
			"syncprov_done_ctrl: ber_flatten2 failed\n",
			0, 0, 0 );
		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
		return ret;
	}

	return LDAP_SUCCESS;
}

static int
syncprov_sendinfo(
	Operation	*op,
	SlapReply	*rs,
	int			type,
	struct berval *cookie,
	int			refreshDone,
	BerVarray	syncUUIDs,
	int			refreshDeletes )
{
	BerElementBuffer berbuf;
	BerElement *ber = (BerElement *)&berbuf;
	struct berval rspdata;

	int ret;

	ber_init2( ber, NULL, LBER_USE_DER );
	ber_set_option( ber, LBER_OPT_BER_MEMCTX, &op->o_tmpmemctx );

	if ( type ) {
		switch ( type ) {
		case LDAP_TAG_SYNC_NEW_COOKIE:
			ber_printf( ber, "tO", type, cookie );
			break;
		case LDAP_TAG_SYNC_REFRESH_DELETE:
		case LDAP_TAG_SYNC_REFRESH_PRESENT:
			ber_printf( ber, "t{", type );
			if ( cookie ) {
				ber_printf( ber, "O", cookie );
			}
			if ( refreshDone == 0 ) {
				ber_printf( ber, "b", refreshDone );
			}
			ber_printf( ber, "N}" );
			break;
		case LDAP_TAG_SYNC_ID_SET:
			ber_printf( ber, "t{", type );
			if ( cookie ) {
				ber_printf( ber, "O", cookie );
			}
			if ( refreshDeletes == 1 ) {
				ber_printf( ber, "b", refreshDeletes );
			}
			ber_printf( ber, "[W]", syncUUIDs );
			ber_printf( ber, "N}" );
			break;
		default:
			Debug( LDAP_DEBUG_TRACE,
				"syncprov_sendinfo: invalid syncinfo type (%d)\n",
				type, 0, 0 );
			return LDAP_OTHER;
		}
	}

	ret = ber_flatten2( ber, &rspdata, 0 );

	if ( ret < 0 ) {
		Debug( LDAP_DEBUG_TRACE,
			"syncprov_sendinfo: ber_flatten2 failed\n",
			0, 0, 0 );
		send_ldap_error( op, rs, LDAP_OTHER, "internal error" );
		return ret;
	}

	rs->sr_rspoid = LDAP_SYNC_INFO;
	rs->sr_rspdata = &rspdata;
	send_ldap_intermediate( op, rs );
	rs->sr_rspdata = NULL;
	ber_free_buf( ber );

	return LDAP_SUCCESS;
}

/* Find a modtarget in an AVL tree */
static int
sp_avl_cmp( const void *c1, const void *c2 )
{
	const modtarget *m1, *m2;
	int rc;

	m1 = c1; m2 = c2;
	rc = m1->mt_op->o_req_ndn.bv_len - m2->mt_op->o_req_ndn.bv_len;

	if ( rc ) return rc;
	return ber_bvcmp( &m1->mt_op->o_req_ndn, &m2->mt_op->o_req_ndn );
}

/* syncprov_findbase:
 *   finds the true DN of the base of a search (with alias dereferencing) and
 * checks to make sure the base entry doesn't get replaced with a different
 * entry (e.g., swapping trees via ModDN, or retargeting an alias). If a
 * change is detected, any persistent search on this base must be terminated /
 * reloaded.
 *   On the first call, we just save the DN and entryID. On subsequent calls
 * we compare the DN and entryID with the saved values.
 */
static int
findbase_cb( Operation *op, SlapReply *rs )
{
	slap_callback *sc = op->o_callback;

	if ( rs->sr_type == REP_SEARCH && rs->sr_err == LDAP_SUCCESS ) {
		fbase_cookie *fc = sc->sc_private;

		/* If no entryID, we're looking for the first time.
		 * Just store whatever we got.
		 */
		if ( fc->fss->s_eid == NOID ) {
			fc->fbase = 2;
			fc->fss->s_eid = rs->sr_entry->e_id;
			ber_dupbv( &fc->fss->s_base, &rs->sr_entry->e_nname );

		} else if ( rs->sr_entry->e_id == fc->fss->s_eid &&
			dn_match( &rs->sr_entry->e_nname, &fc->fss->s_base )) {

		/* OK, the DN is the same and the entryID is the same. */
			fc->fbase = 1;
		}
	}
	if ( rs->sr_err != LDAP_SUCCESS ) {
		Debug( LDAP_DEBUG_ANY, "findbase failed! %d\n", rs->sr_err,0,0 );
	}
	return LDAP_SUCCESS;
}

static Filter generic_filter = { LDAP_FILTER_PRESENT, { 0 }, NULL };
static struct berval generic_filterstr = BER_BVC("(objectclass=*)");

static int
syncprov_findbase( Operation *op, fbase_cookie *fc )
{
	opcookie *opc = op->o_callback->sc_private;
	slap_overinst *on = opc->son;

	/* Use basic parameters from syncrepl search, but use
	 * current op's threadctx / tmpmemctx
	 */
	ldap_pvt_thread_mutex_lock( &fc->fss->s_mutex );
	if ( fc->fss->s_flags & PS_FIND_BASE ) {
		slap_callback cb = {0};
		Operation fop;
		SlapReply frs = { REP_RESULT };
		int rc;

		fc->fss->s_flags ^= PS_FIND_BASE;
		ldap_pvt_thread_mutex_unlock( &fc->fss->s_mutex );

		fop = *fc->fss->s_op;

		fop.o_hdr = op->o_hdr;
		fop.o_bd = op->o_bd;
		fop.o_time = op->o_time;
		fop.o_tincr = op->o_tincr;

		cb.sc_response = findbase_cb;
		cb.sc_private = fc;

		fop.o_sync_mode = 0;	/* turn off sync mode */
		fop.o_managedsait = SLAP_CONTROL_CRITICAL;
		fop.o_callback = &cb;
		fop.o_tag = LDAP_REQ_SEARCH;
		fop.ors_scope = LDAP_SCOPE_BASE;
		fop.ors_limit = NULL;
		fop.ors_slimit = 1;
		fop.ors_tlimit = SLAP_NO_LIMIT;
		fop.ors_attrs = slap_anlist_no_attrs;
		fop.ors_attrsonly = 1;
		fop.ors_filter = &generic_filter;
		fop.ors_filterstr = generic_filterstr;

		fop.o_bd->bd_info = on->on_info->oi_orig;
		rc = fop.o_bd->be_search( &fop, &frs );
		fop.o_bd->bd_info = (BackendInfo *)on;
	} else {
		ldap_pvt_thread_mutex_unlock( &fc->fss->s_mutex );
		fc->fbase = 1;
	}

	/* After the first call, see if the fdn resides in the scope */
	if ( fc->fbase == 1 ) {
		switch ( fc->fss->s_op->ors_scope ) {
		case LDAP_SCOPE_BASE:
			fc->fscope = dn_match( fc->fdn, &fc->fss->s_base );
			break;
		case LDAP_SCOPE_ONELEVEL: {
			struct berval pdn;
			dnParent( fc->fdn, &pdn );
			fc->fscope = dn_match( &pdn, &fc->fss->s_base );
			break; }
		case LDAP_SCOPE_SUBTREE:
			fc->fscope = dnIsSuffix( fc->fdn, &fc->fss->s_base );
			break;
#ifdef LDAP_SCOPE_SUBORDINATE
		case LDAP_SCOPE_SUBORDINATE:
			fc->fscope = dnIsSuffix( fc->fdn, &fc->fss->s_base ) &&
				!dn_match( fc->fdn, &fc->fss->s_base );
			break;
#endif
		}
	}

	if ( fc->fbase )
		return LDAP_SUCCESS;

	/* If entryID has changed, then the base of this search has
	 * changed. Invalidate the psearch.
	 */
	return LDAP_NO_SUCH_OBJECT;
}

/* syncprov_findcsn:
 *   This function has three different purposes, but they all use a search
 * that filters on entryCSN so they're combined here.
 * 1: at startup time, after a contextCSN has been read from the database,
 * we search for all entries with CSN >= contextCSN in case the contextCSN
 * was not checkpointed at the previous shutdown.
 *
 * 2: when the current contextCSN is known and we have a sync cookie, we search
 * for one entry with CSN = the cookie CSN. If not found, try <= cookie CSN.
 * If an entry is found, the cookie CSN is valid, otherwise it is stale.
 *
 * 3: during a refresh phase, we search for all entries with CSN <= the cookie
 * CSN, and generate Present records for them. We always collect this result
 * in SyncID sets, even if there's only one match.
 */
typedef enum find_csn_t {
	FIND_MAXCSN	= 1,
	FIND_CSN	= 2,
	FIND_PRESENT	= 3
} find_csn_t;

static int
findmax_cb( Operation *op, SlapReply *rs )
{
	if ( rs->sr_type == REP_SEARCH && rs->sr_err == LDAP_SUCCESS ) {
		struct berval *maxcsn = op->o_callback->sc_private;
		Attribute *a = attr_find( rs->sr_entry->e_attrs,
			slap_schema.si_ad_entryCSN );

		if ( a && ber_bvcmp( &a->a_vals[0], maxcsn ) > 0 ) {
			maxcsn->bv_len = a->a_vals[0].bv_len;
			strcpy( maxcsn->bv_val, a->a_vals[0].bv_val );
		}
	}
	return LDAP_SUCCESS;
}

static int
findcsn_cb( Operation *op, SlapReply *rs )
{
	slap_callback *sc = op->o_callback;

	if ( rs->sr_type == REP_SEARCH && rs->sr_err == LDAP_SUCCESS ) {
		sc->sc_private = (void *)1;
	}
	return LDAP_SUCCESS;
}

/* Build a list of entryUUIDs for sending in a SyncID set */

#define UUID_LEN	16

typedef struct fpres_cookie {
	int num;
	BerVarray uuids;
	char *last;
} fpres_cookie;

static int
findpres_cb( Operation *op, SlapReply *rs )
{
	slap_callback *sc = op->o_callback;
	fpres_cookie *pc = sc->sc_private;
	Attribute *a;
	int ret = SLAP_CB_CONTINUE;

	switch ( rs->sr_type ) {
	case REP_SEARCH:
		a = attr_find( rs->sr_entry->e_attrs, slap_schema.si_ad_entryUUID );
		if ( a ) {
			pc->uuids[pc->num].bv_val = pc->last;
			AC_MEMCPY( pc->uuids[pc->num].bv_val, a->a_nvals[0].bv_val,
				pc->uuids[pc->num].bv_len );
			pc->num++;
			pc->last = pc->uuids[pc->num].bv_val;
			pc->uuids[pc->num].bv_val = NULL;
		}
		ret = LDAP_SUCCESS;
		if ( pc->num != SLAP_SYNCUUID_SET_SIZE )
			break;
		/* FALLTHRU */
	case REP_RESULT:
		ret = rs->sr_err;
		if ( pc->num ) {
			ret = syncprov_sendinfo( op, rs, LDAP_TAG_SYNC_ID_SET, NULL,
				0, pc->uuids, 0 );
			pc->uuids[pc->num].bv_val = pc->last;
			pc->num = 0;
			pc->last = pc->uuids[0].bv_val;
		}
		break;
	default:
		break;
	}
	return ret;
}

static int
syncprov_findcsn( Operation *op, find_csn_t mode )
{
	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
	syncprov_info_t		*si = on->on_bi.bi_private;

	slap_callback cb = {0};
	Operation fop;
	SlapReply frs = { REP_RESULT };
	char buf[LDAP_LUTIL_CSNSTR_BUFSIZE + STRLENOF("(entryCSN<=)")];
	char cbuf[LDAP_LUTIL_CSNSTR_BUFSIZE];
	struct berval maxcsn;
	Filter cf, af;
#ifdef LDAP_COMP_MATCH
	AttributeAssertion eq = { NULL, BER_BVNULL, NULL };
#else
	AttributeAssertion eq = { NULL, BER_BVNULL };
#endif
	int i, rc = LDAP_SUCCESS;
	fpres_cookie pcookie;
	sync_control *srs = NULL;
	int findcsn_retry = 1;

	if ( mode != FIND_MAXCSN ) {
		srs = op->o_controls[slap_cids.sc_LDAPsync];

		if ( srs->sr_state.ctxcsn.bv_len >= LDAP_LUTIL_CSNSTR_BUFSIZE ) {
			return LDAP_OTHER;
		}
	}

	fop = *op;
	fop.o_sync_mode &= SLAP_CONTROL_MASK;	/* turn off sync_mode */
	/* We want pure entries, not referrals */
	fop.o_managedsait = SLAP_CONTROL_CRITICAL;

	cf.f_ava = &eq;
	cf.f_av_desc = slap_schema.si_ad_entryCSN;
	cf.f_next = NULL;

	fop.o_callback = &cb;
	fop.ors_limit = NULL;
	fop.ors_tlimit = SLAP_NO_LIMIT;
	fop.ors_filter = &cf;
	fop.ors_filterstr.bv_val = buf;

again:
	switch( mode ) {
	case FIND_MAXCSN:
		cf.f_choice = LDAP_FILTER_GE;
		cf.f_av_value = si->si_ctxcsn;
		fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN>=%s)",
			cf.f_av_value.bv_val );
		fop.ors_attrsonly = 0;
		fop.ors_attrs = csn_anlist;
		fop.ors_slimit = SLAP_NO_LIMIT;
		cb.sc_private = &maxcsn;
		cb.sc_response = findmax_cb;
		strcpy( cbuf, si->si_ctxcsn.bv_val );
		maxcsn.bv_val = cbuf;
		maxcsn.bv_len = si->si_ctxcsn.bv_len;
		break;
	case FIND_CSN:
		cf.f_av_value = srs->sr_state.ctxcsn;
		/* Look for exact match the first time */
		if ( findcsn_retry ) {
			cf.f_choice = LDAP_FILTER_EQUALITY;
			fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN=%s)",
				cf.f_av_value.bv_val );
		/* On retry, look for <= */
		} else {
			cf.f_choice = LDAP_FILTER_LE;
			fop.ors_filterstr.bv_len = sprintf( buf, "(entryCSN<=%s)",
				cf.f_av_value.bv_val );
		}
		fop.ors_attrsonly = 1;
		fop.ors_attrs = slap_anlist_no_attrs;
		fop.ors_slimit = 1;
		cb.sc_private = NULL;
		cb.sc_response = findcsn_cb;
		break;
	case FIND_PRESENT:
		af.f_choice = LDAP_FILTER_AND;
		af.f_next = NULL;
		af.f_and = &cf;
		cf.f_choice = LDAP_FILTER_LE;
		cf.f_av_value = srs->sr_state.ctxcsn;
		cf.f_next = op->ors_filter;
		fop.ors_filter = &af;
		filter2bv_x( &fop, fop.ors_filter, &fop.ors_filterstr );
		fop.ors_attrsonly = 0;
		fop.ors_attrs = uuid_anlist;
		fop.ors_slimit = SLAP_NO_LIMIT;
		cb.sc_private = &pcookie;
		cb.sc_response = findpres_cb;
		pcookie.num = 0;

		/* preallocate storage for a full set */
		pcookie.uuids = op->o_tmpalloc( (SLAP_SYNCUUID_SET_SIZE+1) *
			sizeof(struct berval) + SLAP_SYNCUUID_SET_SIZE * UUID_LEN,
			op->o_tmpmemctx );
		pcookie.last = (char *)(pcookie.uuids + SLAP_SYNCUUID_SET_SIZE+1);
		pcookie.uuids[0].bv_val = pcookie.last;
		pcookie.uuids[0].bv_len = UUID_LEN;
		for (i=1; i<SLAP_SYNCUUID_SET_SIZE; i++) {
			pcookie.uuids[i].bv_val = pcookie.uuids[i-1].bv_val + UUID_LEN;
			pcookie.uuids[i].bv_len = UUID_LEN;
		}
		break;
	}

	fop.o_bd->bd_info = on->on_info->oi_orig;
	fop.o_bd->be_search( &fop, &frs );
	fop.o_bd->bd_info = (BackendInfo *)on;

	switch( mode ) {
	case FIND_MAXCSN:
		strcpy( si->si_ctxcsnbuf, maxcsn.bv_val );
		si->si_ctxcsn.bv_len = maxcsn.bv_len;
		break;
	case FIND_CSN:
		/* If matching CSN was not found, invalidate the context. */
		if ( !cb.sc_private ) {
			/* If we didn't find an exact match, then try for <= */
			if ( findcsn_retry ) {
				findcsn_retry = 0;
				goto again;
			}
			rc = LDAP_NO_SUCH_OBJECT;
		}
		break;
	case FIND_PRESENT:
		op->o_tmpfree( pcookie.uuids, op->o_tmpmemctx );
		op->o_tmpfree( fop.ors_filterstr.bv_val, op->o_tmpmemctx );
		break;
	}

	return rc;
}

static void
syncprov_free_syncop( syncops *so )
{
	syncres *sr, *srnext;
	GroupAssertion *ga, *gnext;

	ldap_pvt_thread_mutex_lock( &so->s_mutex );
	if ( --so->s_inuse > 0 ) {
		ldap_pvt_thread_mutex_unlock( &so->s_mutex );
		return;
	}
	ldap_pvt_thread_mutex_unlock( &so->s_mutex );
	if ( so->s_flags & PS_IS_DETACHED ) {
		filter_free( so->s_op->ors_filter );
		for ( ga = so->s_op->o_groups; ga; ga=gnext ) {
			gnext = ga->ga_next;
			ch_free( ga );
		}
		ch_free( so->s_op );
	}
	ch_free( so->s_base.bv_val );
	for ( sr=so->s_res; sr; sr=srnext ) {
		srnext = sr->s_next;
		ch_free( sr );
	}
	ldap_pvt_thread_mutex_destroy( &so->s_mutex );
	ch_free( so );
}

/* Send a persistent search response */
static int
syncprov_sendresp( Operation *op, opcookie *opc, syncops *so,
	Entry **e, int mode )
{
	slap_overinst *on = opc->son;

	SlapReply rs = { REP_SEARCH };
	LDAPControl *ctrls[2];
	struct berval cookie;
	Entry e_uuid = {0};
	Attribute a_uuid = {0};

	if ( so->s_op->o_abandon )
		return SLAPD_ABANDON;

	ctrls[1] = NULL;
	slap_compose_sync_cookie( op, &cookie, &opc->sctxcsn, so->s_rid );

	e_uuid.e_attrs = &a_uuid;
	a_uuid.a_desc = slap_schema.si_ad_entryUUID;
	a_uuid.a_nvals = &opc->suuid;
	rs.sr_err = syncprov_state_ctrl( op, &rs, &e_uuid,
		mode, ctrls, 0, 1, &cookie );
	op->o_tmpfree( cookie.bv_val, op->o_tmpmemctx );

	rs.sr_ctrls = ctrls;
	op->o_bd->bd_info = (BackendInfo *)on->on_info;
	switch( mode ) {
	case LDAP_SYNC_ADD:
		rs.sr_entry = *e;
		if ( rs.sr_entry->e_private )
			rs.sr_flags = REP_ENTRY_MUSTRELEASE;
		if ( opc->sreference ) {
			rs.sr_ref = get_entry_referrals( op, rs.sr_entry );
			send_search_reference( op, &rs );
			ber_bvarray_free( rs.sr_ref );
			if ( !rs.sr_entry )
				*e = NULL;
			break;
		}
		/* fallthru */
	case LDAP_SYNC_MODIFY:
		rs.sr_entry = *e;
		if ( rs.sr_entry->e_private )
			rs.sr_flags = REP_ENTRY_MUSTRELEASE;
		rs.sr_attrs = op->ors_attrs;
		send_search_entry( op, &rs );
		if ( !rs.sr_entry )
			*e = NULL;
		break;
	case LDAP_SYNC_DELETE:
		e_uuid.e_attrs = NULL;
		e_uuid.e_name = opc->sdn;
		e_uuid.e_nname = opc->sndn;
		rs.sr_entry = &e_uuid;
		if ( opc->sreference ) {
			struct berval bv = BER_BVNULL;
			rs.sr_ref = &bv;
			send_search_reference( op, &rs );
		} else {
			send_search_entry( op, &rs );
		}
		break;
	default:
		assert(0);
	}
	/* In case someone else freed it already? */
	if ( rs.sr_ctrls ) {
		op->o_tmpfree( rs.sr_ctrls[0], op->o_tmpmemctx );
		rs.sr_ctrls = NULL;
	}

	return rs.sr_err;
}

/* Play back queued responses */
static int
syncprov_qplay( Operation *op, slap_overinst *on, syncops *so )
{
	syncres *sr;
	Entry *e;
	opcookie opc;
	int rc;

	opc.son = on;
	op->o_bd->bd_info = (BackendInfo *)on->on_info;

	for (;;) {
		ldap_pvt_thread_mutex_lock( &so->s_mutex );
		sr = so->s_res;
		if ( sr )
			so->s_res = sr->s_next;
		if ( !so->s_res )
			so->s_restail = NULL;
		ldap_pvt_thread_mutex_unlock( &so->s_mutex );

		if ( !sr || so->s_op->o_abandon )
			break;

		opc.sdn = sr->s_dn;
		opc.sndn = sr->s_ndn;
		opc.suuid = sr->s_uuid;
		opc.sctxcsn = sr->s_csn;
		opc.sreference = sr->s_isreference;
		e = NULL;

		if ( sr->s_mode != LDAP_SYNC_DELETE ) {
			rc = be_entry_get_rw( op, &opc.sndn, NULL, NULL, 0, &e );
			if ( rc ) {
				ch_free( sr );
				continue;
			}
		}
		rc = syncprov_sendresp( op, &opc, so, &e, sr->s_mode );

		if ( e ) {
			be_entry_release_rw( op, e, 0 );
		}

		ch_free( sr );

		if ( rc )
			break;
	}
	op->o_bd->bd_info = (BackendInfo *)on;
	return rc;
}

/* runqueue task for playing back queued responses */
static void *
syncprov_qtask( void *ctx, void *arg )
{
	struct re_s *rtask = arg;
	syncops *so = rtask->arg;
	slap_overinst *on = so->s_op->o_private;
	OperationBuffer opbuf;
	Operation *op;
	BackendDB be;

	op = (Operation *) &opbuf;
	*op = *so->s_op;
	op->o_hdr = (Opheader *)(op+1);
	op->o_controls = (void **)(op->o_hdr+1);
	memset( op->o_controls, 0, SLAP_MAX_CIDS * sizeof(void *));

	*op->o_hdr = *so->s_op->o_hdr;

	op->o_tmpmemctx = slap_sl_mem_create(SLAP_SLAB_SIZE, SLAP_SLAB_STACK, ctx);
	op->o_tmpmfuncs = &slap_sl_mfuncs;
	op->o_threadctx = ctx;

	/* syncprov_qplay expects a fake db */
	be = *so->s_op->o_bd;
	be.be_flags |= SLAP_DBFLAG_OVERLAY;
	op->o_bd = &be;
	op->o_private = NULL;
	op->o_callback = NULL;

	syncprov_qplay( op, on, so );

	/* decrement use count... */
	syncprov_free_syncop( so );

	/* wait until we get explicitly scheduled again */
	ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
	ldap_pvt_runqueue_stoptask( &slapd_rq, so->s_qtask );
	ldap_pvt_runqueue_resched( &slapd_rq, so->s_qtask, 1 );
	ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );

	return NULL;
}

/* Queue a persistent search response */
static int
syncprov_qresp( opcookie *opc, syncops *so, int mode )
{
	syncres *sr;

	sr = ch_malloc(sizeof(syncres) + opc->suuid.bv_len + 1 +
		opc->sdn.bv_len + 1 + opc->sndn.bv_len + 1 + opc->sctxcsn.bv_len + 1 );
	sr->s_next = NULL;
	sr->s_dn.bv_val = (char *)(sr + 1);
	sr->s_dn.bv_len = opc->sdn.bv_len;
	sr->s_mode = mode;
	sr->s_isreference = opc->sreference;
	sr->s_ndn.bv_val = lutil_strcopy( sr->s_dn.bv_val,
		 opc->sdn.bv_val ) + 1;
	sr->s_ndn.bv_len = opc->sndn.bv_len;
	sr->s_uuid.bv_val = lutil_strcopy( sr->s_ndn.bv_val,
		 opc->sndn.bv_val ) + 1;
	sr->s_uuid.bv_len = opc->suuid.bv_len;
	AC_MEMCPY( sr->s_uuid.bv_val, opc->suuid.bv_val, opc->suuid.bv_len );
	sr->s_csn.bv_val = sr->s_uuid.bv_val + sr->s_uuid.bv_len + 1;
	sr->s_csn.bv_len = opc->sctxcsn.bv_len;
	strcpy( sr->s_csn.bv_val, opc->sctxcsn.bv_val );

	ldap_pvt_thread_mutex_lock( &so->s_mutex );
	if ( !so->s_res ) {
		so->s_res = sr;
	} else {
		so->s_restail->s_next = sr;
	}
	so->s_restail = sr;

	/* If the base of the psearch was modified, check it next time round */
	if ( so->s_flags & PS_WROTE_BASE ) {
		so->s_flags ^= PS_WROTE_BASE;
		so->s_flags |= PS_FIND_BASE;
	}
	if ( so->s_flags & PS_IS_DETACHED ) {
		ldap_pvt_thread_mutex_lock( &slapd_rq.rq_mutex );
		if ( !so->s_qtask ) {
			so->s_qtask = ldap_pvt_runqueue_insert( &slapd_rq, RUNQ_INTERVAL,
				syncprov_qtask, so, "syncprov_qtask",
				so->s_op->o_conn->c_peer_name.bv_val );
			++so->s_inuse;
		} else {
			if (!ldap_pvt_runqueue_isrunning( &slapd_rq, so->s_qtask ) &&
				!so->s_qtask->next_sched.tv_sec ) {
				so->s_qtask->interval.tv_sec = 0;
				ldap_pvt_runqueue_resched( &slapd_rq, so->s_qtask, 0 );
				so->s_qtask->interval.tv_sec = RUNQ_INTERVAL;
				++so->s_inuse;
			}
		}
		ldap_pvt_thread_mutex_unlock( &slapd_rq.rq_mutex );
	}
	ldap_pvt_thread_mutex_unlock( &so->s_mutex );
	return LDAP_SUCCESS;
}

static int
syncprov_drop_psearch( syncops *so, int lock )
{
	if ( so->s_flags & PS_IS_DETACHED ) {
		if ( lock )
			ldap_pvt_thread_mutex_lock( &so->s_op->o_conn->c_mutex );
		so->s_op->o_conn->c_n_ops_executing--;
		so->s_op->o_conn->c_n_ops_completed++;
		LDAP_STAILQ_REMOVE( &so->s_op->o_conn->c_ops, so->s_op, slap_op,
			o_next );
		if ( lock )
			ldap_pvt_thread_mutex_unlock( &so->s_op->o_conn->c_mutex );
	}
	syncprov_free_syncop( so );

	return 0;
}

static int
syncprov_ab_cleanup( Operation *op, SlapReply *rs )
{
	slap_callback *sc = op->o_callback;
	op->o_callback = sc->sc_next;
	syncprov_drop_psearch( op->o_callback->sc_private, 0 );
	op->o_tmpfree( sc, op->o_tmpmemctx );
	return 0;
}

static int
syncprov_op_abandon( Operation *op, SlapReply *rs )
{
	slap_overinst		*on = (slap_overinst *)op->o_bd->bd_info;
	syncprov_info_t		*si = on->on_bi.bi_private;
	syncops *so, *soprev;

	ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
	for ( so=si->si_ops, soprev = (syncops *)&si->si_ops; so;
		soprev=so, so=so->s_next ) {
		if ( so->s_op->o_connid == op->o_connid &&
			so->s_op->o_msgid == op->orn_msgid ) {
				so->s_op->o_abandon = 1;
				soprev->s_next = so->s_next;
				break;
		}
	}
	ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );
	if ( so ) {
		/* Is this really a Cancel exop? */
		if ( op->o_tag != LDAP_REQ_ABANDON ) {
			so->s_op->o_cancel = SLAP_CANCEL_ACK;
			rs->sr_err = LDAP_CANCELLED;
			send_ldap_result( so->s_op, rs );
			if ( so->s_flags & PS_IS_DETACHED ) {
				slap_callback *cb;
				cb = op->o_tmpcalloc( 1, sizeof(slap_callback), op->o_tmpmemctx );
				cb->sc_cleanup = syncprov_ab_cleanup;
				cb->sc_next = op->o_callback;
				cb->sc_private = so;
				return SLAP_CB_CONTINUE;
			}
		}
		syncprov_drop_psearch( so, 0 );
	}
	return SLAP_CB_CONTINUE;
}

/* Find which persistent searches are affected by this operation */
static void
syncprov_matchops( Operation *op, opcookie *opc, int saveit )
{
	slap_overinst *on = opc->son;
	syncprov_info_t		*si = on->on_bi.bi_private;

	fbase_cookie fc;
	syncops *ss, *sprev, *snext;
	Entry *e;
	Attribute *a;
	int rc;
	struct berval newdn;
	int freefdn = 0;

	fc.fdn = &op->o_req_ndn;
	/* compute new DN */
	if ( op->o_tag == LDAP_REQ_MODRDN && !saveit ) {
		struct berval pdn;
		if ( op->orr_nnewSup ) pdn = *op->orr_nnewSup;
		else dnParent( fc.fdn, &pdn );
		build_new_dn( &newdn, &pdn, &op->orr_nnewrdn, op->o_tmpmemctx );
		fc.fdn = &newdn;
		freefdn = 1;
	}
	if ( op->o_tag != LDAP_REQ_ADD ) {
		op->o_bd->bd_info = (BackendInfo *)on->on_info;
		rc = be_entry_get_rw( op, fc.fdn, NULL, NULL, 0, &e );
		/* If we're sending responses now, make a copy and unlock the DB */
		if ( e && !saveit ) {
			Entry *e2 = entry_dup( e );
			be_entry_release_rw( op, e, 0 );
			e = e2;
		}
		op->o_bd->bd_info = (BackendInfo *)on;
		if ( rc ) return;
	} else {
		e = op->ora_e;
	}

	if ( saveit || op->o_tag == LDAP_REQ_ADD ) {
		ber_dupbv_x( &opc->sdn, &e->e_name, op->o_tmpmemctx );
		ber_dupbv_x( &opc->sndn, &e->e_nname, op->o_tmpmemctx );
		opc->sreference = is_entry_referral( e );
		a = attr_find( e->e_attrs, slap_schema.si_ad_entryUUID );
		if ( a )
			ber_dupbv_x( &opc->suuid, &a->a_nvals[0], op->o_tmpmemctx );
	} else if ( op->o_tag == LDAP_REQ_MODRDN && !saveit ) {
		op->o_tmpfree( opc->sndn.bv_val, op->o_tmpmemctx );
		op->o_tmpfree( opc->sdn.bv_val, op->o_tmpmemctx );
		ber_dupbv_x( &opc->sdn, &e->e_name, op->o_tmpmemctx );
		ber_dupbv_x( &opc->sndn, &e->e_nname, op->o_tmpmemctx );
	}

	ldap_pvt_thread_mutex_lock( &si->si_ops_mutex );
	for (ss = si->si_ops, sprev = (syncops *)&si->si_ops; ss;
		sprev = ss, ss=snext)
	{
		syncmatches *sm;
		int found = 0;

		snext = ss->s_next;
		/* validate base */
		fc.fss = ss;
		fc.fbase = 0;
		fc.fscope = 0;

		/* If the base of the search is missing, signal a refresh */
		rc = syncprov_findbase( op, &fc );
		if ( rc != LDAP_SUCCESS ) {
			SlapReply rs = {REP_RESULT};
			send_ldap_error( ss->s_op, &rs, LDAP_SYNC_REFRESH_REQUIRED,
				"search base has changed" );
			sprev->s_next = snext;
			syncprov_drop_psearch( ss, 1 );
			ss = sprev;
			continue;
		}


		/* If we're sending results now, look for this op in old matches */
		if ( !saveit ) {
			syncmatches *old;

			/* Did we modify the search base? */
			if ( dn_match( &op->o_req_ndn, &ss->s_base )) {
				ldap_pvt_thread_mutex_lock( &ss->s_mutex );
				ss->s_flags |= PS_WROTE_BASE;
				ldap_pvt_thread_mutex_unlock( &ss->s_mutex );
			}

			for ( sm=opc->smatches, old=(syncmatches *)&opc->smatches; sm;
				old=sm, sm=sm->sm_next ) {
				if ( sm->sm_op == ss ) {
					found = 1;
					old->sm_next = sm->sm_next;
					op->o_tmpfree( sm, op->o_tmpmemctx );
					break;
				}
			}
		}

		/* check if current o_req_dn is in scope and matches filter */
		if ( fc.fscope && test_filter( op, e, ss->s_op->ors_filter ) ==
			LDAP_COMPARE_TRUE ) {
			if ( saveit ) {
				sm = op->o_tmpalloc( sizeof(syncmatches), op->o_tmpmemctx );
				sm->sm_next = opc->smatches;
				sm->sm_op = ss;
				ldap_pvt_thread_mutex_lock( &ss->s_mutex );
				++ss->s_inuse;
				ldap_pvt_thread_mutex_unlock( &ss->s_mutex );
				opc->smatches = sm;
			} else {
				/* if found send UPDATE else send ADD */
				syncprov_qresp( opc, ss,
					found ? LDAP_SYNC_MODIFY : LDAP_SYNC_ADD );
			}
		} else if ( !saveit && found ) {
			/* send DELETE */
			syncprov_qresp( opc, ss, LDAP_SYNC_DELETE );
		}
	}
	ldap_pvt_thread_mutex_unlock( &si->si_ops_mutex );

	if ( op->o_tag != LDAP_REQ_ADD && e ) {
		op->o_bd->bd_info = (BackendInfo *)on->on_info;
		be_entry_release_rw( op, e, 0 );
		op->o_bd->bd_info = (BackendInfo *)on;
	}
	if ( freefdn ) {
		op->o_tmpfree( fc.fdn->bv_val, op->o_tmpmemctx );
	}
}

static int
syncprov_op_cleanup( Operation *op, SlapReply *rs )
{
	slap_callback *cb = op->o_callback;
	opcookie *opc = cb->sc_private;
	slap_overinst *on = opc->son;
	syncprov_info_t		*si = on->on_bi.bi_private;
	syncmatches *sm, *snext;
	modtarget *mt, mtdummy;